[Role and related mechanisms of LiaSR two-component system in acid tolerance and biofilm formation of Streptococcus mutans].

Objective: To investigate the role and related mechanisms of the LiaSR two-component system in acid tolerance and biofilm formation abilities of Streptococcus mutans (Sm) 593. Methods: The growth curves of various Sm strains in pH=5.5 brian heart infusion (BHI) medium were analyzed. And colony forming unit (CFU) was also performed to evaluate the acid tolerance of Sm. Laurdan probe, H+-K+adenosine triphosphate (ATP)ase activity analysis kit, proton permeability assay and real-time fluorescence quantitative PCR (RT-qPCR) were conducted to detect the acid tolerant mechanisms of LiaSR two-component system in Sm. Crystal violet staining, CFU, SYTOX probe and anthrone-sulfuric method were used to analyze the properties and structures of the Sm biofilms. RT-qPCR was conducted to detect the expression levels of underlying regulated genes. Results: The growth of mutants in acidic BHI were inhibited (P<0.05). The acid tolerance of mutants significantly decreased compared to the wild-type strain (P<0.05). In mutants, the activity of H+-ATPase (917.06±59.53 and 469.53±47.65) were elevated by 7.22-folds and 3.70-folds compared to the wild-type strain (127.00±50.71) (P<0.001, P<0.001) and the encoded gene atpD (3.39±0.21 and 1.94±0.17) were also elevated by 3.39-folds and 1.94-folds compared to the wild-type strain (1.00±0.15) (P<0.001, P=0.001). The Laurdan generalized polarization of mutants (0.18±0.04 and 0.18±0.05) increased significantly compared to the wild-type strain (0.08±0.05) (P=0.006, P=0.003) and the expression levels of fabM gene were decreased in mutants (0.52±0.11 and 0.57±0.05) by 1/2 (P=0.014, P=0.022). In liaR deletion mutant, the reduced terminal pH (4.76±0.01) can also be observed (P<0.001). The total amount of the biofilms of three Sm didn't show significant differences (P>0.05). But the number of viable bacteria of mutants' biofilms were decreased [Sm 593: (12.00±2.80)×107 CFU/ml; Sm ΔliaS: (2.95±1.13)×107 CFU/ml; Sm ΔliaR: (7.25±1.60)×107 CFU/ml] (P=0.001, P=0.024). The extracellular DNA were increased by 18.00-folds and 6.50-folds in mutants' biofilms (128.73±15.65 and 46.38±5.52) compared to the wild-type strain (7.16±3.62) (P<0.001, P=0.003). Water-soluble exopolysaccharides could be found up-regulated in liaS deletion mutant [(138.73±10.12) µg/ml] (P=0.003) along with the expression level of gtfC gene (1.65±0.39) (P=0.014). The expression level of gtfD were elevated by 47.43-folds and 16.90-folds in mutants (P<0.001, P=0.010). Conclusions: The LiaSR two-component system can promote the expression of fabM gene and increase the fluidity of Sm which contributes to acid tolerance. The LiaR can also decrease the proton permeability and restrict the entrance of H+. The LiaSR two-component system can negatively regulate the production of the extracellular matrix in Sm biofilm.

[Ruxolitinib combined with liposomal doxorubicin, etoposide, methylprednisolone+/-PEG-asparaginase in treatment of relapsed/refractory pediatric hemophagocytic lymphohistiocytosis].

Objective: To investigate the efficacy and safety of ruxolitinib, liposomal doxorubicin, etoposide, methylprednisolone+/-PEG-asparaginase (RU-DEP+/-L) in the treatment of relapsed/refractory (R/R) pediatric hemophagocytic lymphohistiocytosis (HLH). Methods: The clinical data of R/R pediatric HLH, who accepted the RU-DEP+/-L regimen at Beijing Children's Hospital from January 2018 to December 2019 was retrospectively analyzed. Results: A total of 16 patients were included in this study, including 13 males and 3 females, aged[M(Q1,Q3)] 1 (1, 2) years at diagnosis. Thirteen patients were diagnosed with Epstein-Barr virus (EBV)-HLH, 2 with EBV-induced primary HLH, and 1 with unclear etiology, among which 3 patients were co-infected with CMV. After the first-line treatment, 11 patients had no response, and 5 patients relapsed after complete response. Nine patients received the RU-L-DEP regimen, and 7 patients received the RU-DEP regimen. The overall response rate and complete response of RU-DEP+/-L treatment were 10/16 and 3/16, respectively. The negative conversion rate of plasma EBV-DNA was 7/15. The median follow-up time was 35.1 (2.4, 40.7) months, and 9/16 patients were survival. The 3-year overall survival rate after RU-DEP+/-L treatment in response and accepted hematopoietic stem cell transplantation (HSCT) was higher than that without response and did not receive HSCT (P=0.048). Among the 16 patients, 9 had varying degrees of myelosuppression, and 13 had an infection. Conclusions: RU-DEP+/-L can be used as a salvage treatment in R/R pediatric HLH, which can provide a bridge to HSCT and play an important role in the control of HLH. The main adverse reactions are myelosuppression and infection, which can be tolerated.

[The association between calcium supplementation in antenatal childbearing aged women and risk of small for gestational age among neonatal singleton in Shaanxi province].

Objective: This study explored the association between antenatal calcium supplementation in the childbearing aged women and risk of small for gestational age infant (SGA) among singleton in Shaanxi province,China. Methods: Multi-stage random cluster sampling method was employed to collect information about pregnant women, who were pregnant and had definite outcomes, and their infants, from 30 districts (counties) in 2010 to 2013. Information was collected by face-to-face questionnaire survey. Generalized linear mixed models were employed after adjusting covariates. Dependent variable was whether single-birth neonate was SGA, and independent variable was calcium supplementation of childbearing aged women in different pregnant periods. Results: A total of 28 357 childbearing aged women was recruited in this study. The age of these women was (28.08±4.74) years old, of which, 79.28% were rural residents and 60.90% had calcium supplementation intake. There was a number of 12 810 female in singleton neonates. The neonatal birth weight and gestational age were (3.27±0.16) kg and (277.44±8.80) day, respectively. The prevalence of SGA was 11.35% in total, and 10.48% in mothers with maternal calcium supplementation and 12.70% in mothers without maternal calcium supplementation in whole antenatal period. There were statistically significant differences seen in antenatal calcium supplementation within the subgroups of maternal age (whether the mother was an advanced maternal woman), residential area, maternal occupation, maternal parity, maternal education level, and household incomes (P<0.05). After adjusting these covariates, the risk of SGA among childbearing aged women with antenatal calcium supplementation showed 16% decreased risk (OR=0.84, 95%CI: 0.77-0.92). Further analysis of the different antenatal periods showed that calcium supplementation during the second and third trimester had a statistically significant difference in reducing the risk of neonatal SGA (P<0.05). Besides, subgroup analysis showed that there was a statistically significant difference between the perinatal calcium supplementation and the single-born neonates with SGA Significance (P<0.05) in non-advanced women, those who had a low education level and moderate household economic status groups. Conclusion: The risk reduction of SGA among singleton neonates is related to calcium supplementation during antenatal period in Shaanxi province.

[Epidemiological characteristics of serum vitamin B(12) and folate levels in women awaiting delivery].

Objectives: To analyze the epidemiological characteristics and levels of vitamin B(12) and folate as well as their relationship in women awaiting delivery, in Shaanxi province. Methods: Data were collected from healthy pregnant women who gave birth at six top hospitals in Shaanxi, from January 2014 to December 2016. Blood samples were taken prenatally to determine the levels of vitamin B(12) and folate. Quantile regression model was used to analyze the relationship between the levels of vitamin B(12) and folates in women awaiting delivery. Results: A total of 1 277 women awaiting delivery were included in this study. Among them, the median level of serum vitamin B(12) was 164.7 pg/ml, in women at late pregnancy, with the deficiency rate as 69.6%, while the median level of serum folate was 7.6 ng/ml, with the deficiency rate as 12.1%. 58.4% of these women presented simple vitamin B(12) deficiency and 0.9% with simple folate deficiency. Women living in rural areas showed lower levels of both vitamin B(12) and folate than the women from the urban areas. Both the levels of vitamin B(12) and folate increased with age but were significantly lower in women under the age of 25. Among those with or without folate deficiency, the average difference in the levels of vitamin B(12) was 37.62 pg/ml. Quantile regression models showed that the vitamin B(12) levels in women with folate deficiency were significantly lower than those without, despite the different levels of vitamin B(12). This difference appeared increasing along with the increase of the vitamin B(12) levels. Conclusions: Our data showed that both vitamin B(12) and folate were deficient in women awaiting delivery, in Shaanxi. We suggest that vitamin B(12) should also be added into the folic acid supplementation program, together with the reinforcement on health education program to improve the awareness of nutrient supplementation in rural and young women. Hopefully, these strategies could increase the levels of both vitamin B(12) and folate, in the province.

[Association between maternal passive smoking during perinatal period and congenital heart disease in their offspring-based on a case-control study].

Objective: To explore the association between maternal passive smoking during perinatal period and congenital heart disease (CHD) in their offspring. Methods: A case-control study was designed. Data being used was based on a case-control study of congenital heart disease collected in Shaanxi province from January 2014 to December 2016. Cases under this study were perinatal infants diagnosed as CHD from 28 weeks of gestation to 7 days after birth, and fetus less than 28 weeks of gestation but diagnosed as CHD by ultrasonography. The controls would include newborn infants without any birth defects, born at the same period of the cases. Logistic regression model with confounding factors adjusted was established to analyze the association between maternal passive smoking status during perinatal period and CHD in their offspring. Subgroup analysis was carried out to explore its stability. Results: A total of 2 259 subjects, consisting 695 cases and 1 564 controls were included in this study. Passive smokers accounted for 26.76% in the case group while only 6.01% in the control group. After adjusting for related confounding factors, the risk of CHD in the offspring of passive smokers was 3.32 times higher than that of the non-passive smokers (OR=3.32, 95%CI: 2.41-4.56), during the perinatal period. Results also showed that related risk accumulated with the increase of exposure frequency to passive smoking. For mothers who smoked passively for 1-3 days per week, the risk of CHD in their offspring was 2.75 times higher than that of those non-passive smokers (OR=2.75, 95%CI: 1.62-4.66). For mothers who smoked passively for more than 3 days per week, the risk was 3.62 times higher than the non-passive smokers (OR=3.62, 95%CI: 2.48-5.29). Data from the subgroup analysis showed that the association between maternal passive smoking during perinatal period and CHD in their offspring appeared stable. Conclusions: Maternal passive smoking during perinatal period seemed a risk factor for congenital heart disease related to their offspring. Pregnant women should avoid exposure to second-hand smoke as much as possible, so as to prevent the harm from passive smoking.

Antidepressant Drugs Correct the Imbalance Between proBDNF/p75NTR/Sortilin and Mature BDNF/TrkB in the Brain of Mice with Chronic Stress.

Depression is a worldwide problem with a great social and economic burden in many countries. In our previous research, we found that the expression of proBDNF/p75NTR/sortilin is upregulated in patients with major depressive disorder. In addition, the treatment of proBDNF antibodies reversed both the depressive behaviors and the reduced BDNF mRNA detected in our rodent chronic stress models. Antidepressant drugs are usually only effective in a subpopulation of patients with major depression with a delayed time window of 2-4 weeks to exert their efficacy. The mechanism underlying such delayed response is not known. In this study, we hypothesize that antidepressant drugs exert their therapeutic effect by modulating proBDNF/p75NTR and mature BDNF/TrkB signaling pathways. To test the hypothesis, C57 mice were randomly divided into normal control, chronic unpredictable mild stress (CUMS), vehicle (VEH), fluoxetine (FLU), and clozapine (CLO) groups. Behavioral tests (sucrose preference, open field, and tail suspension tests) were performed before and after 4 weeks of CUMS. The gene and protein expression of proBDNF, the neurotrophin receptor (p75NTR), sortilin, and TrkB in the cortex and hippocampus were examined. At the protein level, CUMS induced a significant increase in proBDNF, p75NTR, and sortilin production while the TrkB protein level was found to be lower in the cortex and hippocampus compared with the control group. Consistently, at the mRNA level, p75NTR expression increased with reduced BDNF/TrkB mRNA in both cortex and hippocampus, while sortilin increased only in the hippocampus after CUMS. FLU and CLO treatments of CUMS mice reversed all protein and mRNA expression of the biomarkers in both cortex and hippocampus, except for sortilin mRNA in the cortex and proBDNF in the hippocampus, respectively. This study further confirms that the imbalance between proBDNF/p75NTR/sortilin and mBDNF/TrkB production is important in the pathogenesis of depression. It is likely that antidepressant FLU and antipsychotic CLO exert their antidepressant-like effect correcting the imbalance between proBDNF/p75NTR/sortilin and mBDNF/TrkB.

Diminutive Incision Acromioplasty Assisted with Arthroscopy in the Treatment of Chinese Patients with Subacromial Impingement Syndrome / Acromioplastia de Incisión Diminuta Asistida con Artroscopia en el Tratamiento de Pacientes Chinos con Síndrome de Pinzamiento Subacromial

ABSTRACT Background: Many causes can lead to shoulder pain and subacromial impingement syndrome (SIS) is the most frequently recorded disorders. The aim of this study was to evaluate the clinical effects of diminutive incision acromioplasty assisted with arthroscopy for the treatment of Chinese patients with subacromial impingement syndrome. Subject and Methods: Twenty-two patients with 24-painful shoulders subacromial impingement syndrome were enrolled. All painful shoulders were in Grades II (8) and III (16) according to Neer's classification. Detailed physical examination was performed. Conventional radiography and subsequent magnetic resonance imaging (MRI) of the shoulder region of all patients were done. The University of California at Los Angeles Shoulder (UCLA) score system was used for all patients to evaluate their satisfaction after surgery. The preoperative recordings of the UCLA scores were collected and all enrolled cases including 24-painful shoulders were available for follow-up in 1, 3, 6, 12 months after surgery. Results: According to the UCLA scoring system, the symptom of all painful shoulders were improved after one year postoperatively. The average score before surgery from 15.4 points increased to 31.2 points postoperatively, showing a statistical difference (p < 0.05). Conclusions: A diminutive incision acromioplasty assisted with arthroscopy is a reliable approach to treat Chinese patients with subacromial impingement syndrome. All painful shoulders were obviously improved in one year after surgery.

ABSTRACT Antecedentes: Muchas causas pueden provocar dolor de hombro y síndrome de compresión subacromial (SIS) es el trastorno más frecuentemente registrado. El objetivo de este estudio fue evaluar la clínica. Efectos de la acromioplastia con incisión diminuta asistida con artroscopia para el tratamiento de Pacientes chinos con síndrome de pinzamiento subacromial. Sujeto y métodos: Se incluyeron veintidós pacientes con síndrome de afectación subacromial de 24-hombros dolorosos. Todos los hombros dolorosos estaban en Grados II (8) y III (16) de acuerdo con la clasificación de Neer. Se realizó examen físico detallado. Se realizaron radiografías convencionales y, posteriormente, imágenes de resonancia magnética (IRM) de la región del hombro de todos los pacientes. El sistema de puntuación de la Universidad de California en Los Angeles Shoulder (UCLA) se utilizó para que todos los pacientes evaluaran su satisfacción después de la cirugía. Los registros preoperatorios de las puntuaciones de UCLA se recopilaron y todos los casos incluidos, incluidos 24-hombros dolorosos, estaban disponibles para el seguimiento en 1, 3, 6 y 12 meses después de la cirugía. Resultados: De acuerdo con el sistema de puntuación de UCLA, el síntoma de todos los hombros dolorosos mejoró después de un año después de la operación. La puntuación promedio antes de la cirugía de 15.4 puntos aumentó a 31.2 puntos después de la operación, mostrando una diferencia estadística (p < 0.05) Conclusiones: Una acromioplastia de incisión diminuta asistida con artroscopia es un enfoque confiable para tratar a pacientes chinos con síndrome de pinzamiento subacromial. Todas las lesiones dolorosas se mejoraron obviamente en un año después de la cirugía.

miRNA-130a improves cardiac function by down-regulating TNF-α expression in a rat model of heart failure.

OBJECTIVE: To investigate the effect of MicroRNA (miRNA)-130a on cardiac function and the expression of tumor necrosis factor-α (TNF-α) in rats with heart failure. MATERIALS AND METHODS: The rat heart failure model (n = 30) were established, then divided into miRNA-130a group, phosphate-buffer saline (PBS) group, rAAV9 group, and sham group (n = 10 in each group). Four weeks after the operation, the cardiac ultrasound and hemodynamic determination were performed. Blood endothelin-1 (ET-1) content was measured by enzyme-linked immunosorbent assay (ELISA). Hematoxylin and eosin (HE) staining was used to observe the morphology of myocardium. The expression levels of miRNA-130a and TNF-α were determined by quantitative Real Time-Polymerase Chain Reaction) (qRT-PCR). And the expression of TNF-α protein was determined by immunohistochemistry and Western blotting. RESULTS: The rat heart failure model was successfully constructed. The miRNA-130a expression was decreased in rats with heart failure, and miRNA-130a transfection was successful. miRNA-130a improved left ventricular ejection fraction in the rat with heart failure. The blood ET-1 in miRNA-130a group was significantly lower than that of PBS group and rAAV9 group (p < 0.05). RT-PCR, Immunohistochemistry and Western blotting results showed that compared with the sham group, the expression of TNF-α in the model group was increased. And the expression of TNF-α in miRNA-130a group was significantly lower than that of PBS and rAAV9 group. CONCLUSIONS: miRNA-130a could improve cardiac function of heart failure rat by down-regulating TNF-α.

Parameter-specific analgesic effects of electroacupuncture mediated by degree of regulation TRPV1 and P2X3 in inflammatory pain in rats.

AIMS: Observing the parameter-specific anti-hyperalgesic effects of EA with different stimulation times and frequencies on painful hyperalgesia mediated by the level of TRPV1 and P2X3 expression in DRG after CFA injection. MAIN METHODS: The model was induced by the injection of CFA in each rat's right hind paw. EA treatment was applied to the bilateral ST36 and BL60. Paw withdrawal threshold (PWT) and paw withdrawal latency (PWL) were tested with Von Frey filaments and the radiant heat source of the test instrument, respectively. TRPV1 and P2X3 expressions were measured by immunofluorescence and western blot. αß-meATP and capsaicine combined with EA were further utilized to investigate the change in PWL. KEY FINDINGS: Different stimulation times (20, 30, 45 min) combined with different frequencies (2 Hz, 100 Hz, 2/100 Hz) of EA have analgesic effects on the PWT and PWL; however, the level of the hypoalgesic efficacy of EA was primarily associated with EA frequency. The analgesic effect of EA was better at 100 Hz than at 2 Hz. The level of regulation of 100 Hz EA on TRPV1 and P2X3 in DRG was greater than that of 2 Hz. Furthermore, both TRPV1 agonist and P2X3 agonist may impair the level of EA analgesia. SIGNIFICANCE: EA has a parameter-specific effect on chronic inflammatory pain relief, which primarily depend on the stimulation frequency and not on the stimulation time at a certain stimulation time. The parameter-specific analgesic effect of EA is at least partially related to mediation of the protein level of TRPV1 and P2X3 expression in DRG of CFA rats.

[Evaluation of the modified test system for children sound localization].

Objective: To evaluate the feasibility of modified test system for sound localization (SL) in children. Methods: Modified system (6 male, 9 female) and traditional method ( 5 male, 5 female) were used for evaluation of minimum audible angle(MAA) and root-mean-square error(RMS) error of 4 to 6 years old children, and the results were compared to verify the accuracy and effectiveness of the modified test system for children sound localization.SPSS 17.0 software was used to analyze the data(t test). Results: (1) Comparison of veracity of modified system and traditional test: when tested at the positive front position using modified system, MAA and RMS error were(3.23±1.00)° and (13.68±5.18)° respectively.When using traditional method, MAA and RMS error were(3.17±0.59)°and (13.96±4.56)° respectively. No statistical differences were found between two groups(t value was 0.16, -0.14, both P>0.05). (2) Comparison of time used were as followed: when using modified system, it was (14.67±1.95) min for MAA, and (6.67±1.35) min for RMS error. When using traditional method, it was (36.30±6.81) min for MAA, and (21.00±3.50) min for RMS error. Time used were significant shorter in modified system than in traditional method (t value was-9.78, -12.37, both P<0.05). Conclusion: Modified test system for children sound localization is useful and reliable in children's horizontal SL test.The time used of modified test system is shorter than that of traditional test system.

Treatment strategies for early neurological deficits related to malpositioned pedicle screws in the lumbosacral canal: A pilot study.

OBJECTIVES: To employ a simple and fast method to evaluate those patients with neurological deficits and misplaced screws in relatively safe lumbosacral spine, and to determine if it is necessary to undertake revision surgery. METHODS: A total of 316 patients were treated by fixation of lumbar and lumbosacral transpedicle screws at our institution from January 2011 to December 2012. We designed the criteria for post-operative revision scores of pedicle screw malpositioning (PRSPSM) in the lumbosacral canal. We recommend the revision of the misplaced pedicle screw in patients with PRSPSM = 5' as early as possible. However, patients with PRSPSM < 5' need to follow the next consecutive assessment procedures. A total of 15 patients were included according to at least three-stage follow-up. RESULTS: Five patients with neurological complications (PRSPSM = 5') underwent revision surgery at an early stage. The other ten patients with PRSPSM < 5' were treated by conservative methods for seven days. At three-month follow-up, only one patient showed delayed onset of neurological complications (PRSPSM 7') while refusing revision. Seven months later, PRSPSM decreased to 3' with complete rehabilitation. CONCLUSIONS: This study highlights the significance of consecutively dynamic assessments of PRSPSMs, which are unlike previous implementations based on purely anatomical assessment or early onset of neurological deficits.and also confirms our hypothesis that patients with early neurological complications may not need revision procedures in the relatively broad margin of the lumbosacral canal.Cite this article: X-J. Lin. Treatment strategies for early neurological deficits related to malpositioned pedicle screws in the lumbosacral canal: A pilot study. Bone Joint Res 2016;5:46-51.

Identification and functional analysis of differentially expressed genes related to obesity using DNA microarray.

We looked for differentially expressed genes at different stages of preadipocyte differentiation and examined their functions, based on DNA microarrays of preadipocytes obtained from healthy subjects undergoing cosmetic liposuction. We downloaded gene expression profile GSE25910 from the Gene Expression Omnibus database and identified the differentially expressed genes with packages in R language. The selected differentially expressed genes were further analyzed using bioinformatics methods. Comparing gene expression at different stages of preadipocytes differentiation, we found that expression of 668 and 1007 genes were altered in middle and late stages compared with the early stage, respectively. Function analysis revealed that the differentially expressed genes were mainly related to fatty acid metabolic processes in the former two stages.

Effective Resistance to Wheat Stripe Rust in a Region with High Disease Pressure.

Stripe rust is a major fungal disease of wheat. It frequently becomes epidemic in southeastern Gansu province, a stripe rust hot spot in China. Evaluations of wheat germplasm response are crucial for developing cultivars to control the disease. In total, 57 wheat cultivars and lines from Europe and other countries, comprising 36 cultivars with documented stripe rust resistance genes and 21 with unknown genes, were tested annually with multiple races of Puccinia striiformis f. sp. tritici in the field at Tianshui in Gansu province from 1993 to 2013. Seven wheat lines were highly resistant, with infection type (IT) 0 during the entire period; 16 were moderately resistant (IT 0;-2); and 26 were moderately susceptible (IT 0;-4), with low maximum disease severity compared with the susceptible control Huixianhong. 'Strampelli' and 'Libellula', with three and five quantitative trait loci, respectively, for stripe rust resistance have displayed durable resistance in this region for four decades. Ten cultivars, including 'Lantian 15', 'Lantian 26', and 'Lantian 31', with stripe rust resistance derived from European lines, were developed in our breeding program and have made a significant impact on controlling stripe rust in southeastern Gansu. Breeding resistant cultivars with multiple adult-plant resistance genes seems to be a promising strategy in wheat breeding for managing stripe rust in this region and other hot spots.

[Neocartilage formation in vitro using transduced mesenchymal stem cells cultured on biomimetic biodegradable polymer scaffolds].

OBJECTIVE: To investigate the effect of transforming growth factor (TGF) beta 1 gene transfection on the growth of mesenchymal stem cells(MSCs) and to evaluate a new biomimetic biodegradable polymer as scaffolds for applications in articular cartilage tissue engineering. METHODS: Principles of tissue engineering were combined organically with principles of gene therapy to produce cultured periosteum-derived MSCs transduced with the full-length rat TGF-beta 1 cDNA in vitro. These cells were then seeded onto three-dimensional porous poly-DL-lactide scaffolds modified with poly-L-lysine that mimicked cell-binding domains found on natural extracellular matrix to promote specific cell adhesion. The adhesion, proliferation, and differentiation of the transfected MSCs were examined with scanning electron microscope within 2 weeks. RESULTS: All cells adhered to the biomimetic matrices well, but more cartilage-like tissue was formed for TGF-beta 1 gene modified MSCs/scaffolds composites than for the control groups. Transfer of gene encoding TGF-beta 1 to MSCs promoted its proliferation and differentiation significantly. CONCLUSIONS: The TGF-beta 1 gene transduced MSCs/biomimetic matrix composites used in this study was the first attempt to apply the principles of molecular tissue engineering for articular cartilage repair. This new molecular tissue engineering approach could be of potential benefit to repair damaged articular cartilage, especially in osteoarthritis. The new biomimetic biodegradable polymer matrices modified with biomolecules not only have good structural compatibility, but also have better interfacial compatibility and bioactivity, and can be used as scaffolds for articular cartilage tissue engineering.

[Determination of degraded products of penicillin by high performance liquid chromatography].

A method for the determination of main composition in degraded products of penicillin, 6-aminopenicillanic acid (6-APA), penicillin G kalium (PGK), phenylacetic acid (PAA), and the by-product benzylpenicilloic acid (BPA) by HPLC was studied. Separation conditions were as follows: Spherisorb C18 column, 250 mm x 4.6 mm i.d., 10 micrograms; mobile phase: V (methanol): V(0.004 mol/L KH2PO4 buffer, pH 4.5) = 50:50; flow rate: 1 mL/min; detector: UV 230 nm. The method is effective, quick, accurate and reproducible. The satisfactory results show that this new method has certain practical values as an approach of quality control.

[Effects of acute mild and moderate hypoxia on human short memory].

OBJECTIVE: To investigate the effects of acute mild and moderate hypoxia on human short memory. METHOD: Tests of pattern memory, scanning memory, continuous recognition memory and space memory were conducted on 18 healthy young male subjects during exposure to 300 m (control), 2800 m, 3600 m and 4400 m altitude in hypobaric chamber. RESULT: Compared to control group, only the performance of continous recognition memory decreased significantly after exposure to 2800 in for 1 h(P < 0. 05); total reaction time in all tests increased significantly (P < 0.0 1) and performance decreased after exposure to 3600 in for 1 h, but the error rates in memory scanning and space memory test were unchanged (P > 0.05); during exposure to 4400 in performance of all tests decreased further to about 90.4%, 93.7%, 83.3% and 80.7% of the control values (P < 0.01), respectively,and error rate increased significantly too (P < 0.05). CONCLUSION: Performance of human short memory decreased after exposure to acute mild and moderate hypoxia for 1 h, and these effects were aggravated with the increase of altitude. Characteristic and threshold of the effect on the various performance tests were different, but increase of reaction time was the first to appear in all cases.

Biomechanical study on osteotomized tibias fixed with unilateral adjustable external fixator.

Five fresh tibias removed from 30-40 years old dead males were osteotomized at one-third supra-medium segment and then fixed by an unilateral adjustable external fixator (UAEF) to be used as a model of external fixation of tibial fracture. For each loading test under different configurations of UAEF, the ratio of the force-displacement was used to determine its stiffness value. The weakest mode of the UAEF device is in AP bending. Under each mode of compression, distraction, anteroposterial and lateral bending and torsion loading, increasing the pin number or pin diameter or pin separation, and/or reduction of pin group separation can significantly increase the stiffness values of UAEF (P < 0.01). These data revealed that UAEF is suitable for the external fixation of tibial fracture.

An abduction-traction frame for the treatment of intertrochanteric fracture of femur.

We present a detailed outline of treatment of intertrochanteric fractures of femur with a new technique on the basis of principles of combined traditional chinese and western medicine. We use pins and an outer fixation frame, which keeps the injured limb in abduction and under traction and at the same time allows for functional exercise of all the joints in the extremity. The procedure is discussed and compared with other different techniques.

Comparison of effects of MPTCP and PTCP ceramics implanted for the treatment of bone defects in rabbits.

The magnetic porous tricalcium phosphate (MPTCP) and porous tricalcium phosphate (PTCP) ceramic cylinders were implanted into right and left bone defects of rabbits' radii in order to determine the utility of the MPTCP ceramics. Based on naked eye inspection, light and scanning electron microphotography, roentgenography, quantitative histological measurement of new bone formation and anti-break test for a period of 5 months. The results showed that the two kinds of ceramics were biocompatible with human tissue. MPTCP ceramics could induce more new bone formation than PTCP ceramics. Treatment of fractures with synthetic calcium phosphate ceramics and magnetic fields were discussed.